The present invention generally relates to vibratory (shaker) conveyors for moving goods along a conveyor tray, and more particularly to a rotary drive mechanism for powering vibratory conveyors.
A vibratory conveyor includes a generally elongate horizontal or slightly inclined tray or pan having a planar surface. The tray is moved slowly forward to shift the goods, relative to the planar surface of the tray, and is then pulled rearwardly at a high return speed so that the goods slide along the planar surface of the tray. In this way, the goods are effectively transported along the conveyor tray. Vibratory conveyors, which are sometimes referred to as differential impulse conveyors, linear motion conveyors, or shaker conveyors provide a significant advantage in that goods may be transported along the tray in a manner that does not require engagement with the parts by secondary fixtures or the like (no moving tray parts) which could damage the goods.
Various prior art mechanisms for driving vibratory conveyors are known in the art including reciprocating pistons, driven three and four bar linkages, and mechanisms employing a plurality of flywheels suspended from the tray. For example U.S. Pat. Nos.: 6,079,548; 5,850,906; 5,794,757; 5,699,897; 5,579,890; 5,404,996; 5,351,807; 4,436,199; 4,339,029; and 4,019,626 disclose drive mechanisms suitable for use with vibratory conveyors. Prior art drive mechanisms that utilize one or more flywheels such that the momentum of the rotating flywheels achieve the desired slow forward speed and high return speed for the conveyor tray have been found to be costly and not easily optimized to adjust the ratio of forward acceleration to return acceleration to achieve the desired product speed along the tray.
In U.S. Pat. No. 4,339,029, issued to Wilson, a shaker conveyor is provided that uses rotary motion to develop reciprocating motion in a parts conveyor tray. The use of a shaker conveyor results in the use of a smaller drive system achieving the desired movement of the articles along the shaker conveyor. Wilson""s rotary drive system includes a fly wheel that is connected to a power source. The fly wheel""s axle is centrally and rotatably mounted on to the fly wheel, with the upper face of the fly wheel being parallel to the surface of the tray. An eccentric is secured to the upper face of the fly wheel by welding, bolting, or machining so that it is always disposed in fixed spaced relation to the central rotational axis of the fly wheel. A reciprocating plate having a bearing is attached to the other end of the eccentric. The reciprocating plate is mounted within a reciprocating plate bearing, and is secured to the tray. It is the rotation of the fly wheel in combination with the eccentric communicating with the reciprocating plate and an eccentric bearing which results in the reciprocating motion of the tray. The reciprocating motion of the tray is linear and parallel to the fly wheel and the reciprocating plate. Thus Wilson discloses a fly wheel revolving about a fly wheel axle to transmit reciprocating motion through a fixed eccentric, and thereby permitting rotary motion to be converted directly into linear reciprocating motion.
A vibratory conveyor drive is provided that is operatively connected to a vibratory conveyor tray for use in generating reciprocating movement in the tray so that a variety of goods may be transported along the tray. The vibratory conveyor drive is adapted for use in a vibratory conveyor system for conveying materials, and is often supported by a frame with the tray slidingly supported by the frame. The conveyor drive of the invention includes a drive wheel having a radial slot formed in it. The drive wheel is supported for rotation about a first axis of rotation and is operatively connected to a source of rotational motive force, such as an electric motor. A transfer wheel is supported for rotation about a second axis of rotation, and is positioned in substantially parallel-spaced relation to the drive wheel. The transfer wheel includes a first shaft projecting outwardly from a first surface, with a drive-follower positioned on an end of the first shaft. The drive-follower is received within the radial slot of the drive wheel. An axle projects outwardly from a second surface of the transfer wheel, and is positioned in coaxial relation with the second axis of rotation. A reciprocating arm having first and second ends is secured to the axle at the first end in substantially parallel-spaced relation to the transfer wheel. The reciprocating arm includes a drive shaft projecting outwardly from the second end, and has a tray-follower positioned in a tray driver that is mounted on to a portion of the tray so as to transfer the reciprocating movement to of the vibratory conveyor drive the tray.